The present invention relates to devices for capturing the power of wind, and more particularly to such devices wherein a wind power is converted to rotational mechanical energy.
More particularly, the present invention relates to windmill having an axis of rotation which is oriented generally perpendicular with respect to the surface of the earth, or so-called vertical axis windmills. Windmills of the above mentioned general type are known in the art. One of such windmills is disclosed in our U.S. Pat. No. 4,822,239. The existing windmills with a vertical axis of rotation operate in a horizontal plane and, in addition to the useful energy, give away a significant part of it for compensation of mechanical, hydraulic, and aerodynamic losses. Such losses include losses for friction in a rotary mechanism, friction of blades in contact with air, losses connected with viscosity of air which causes sticking of airstreams on the blades, braking whirling, etc. The main loss is however loss for a front resistance of blades. It is believed to be advisable to further improve the existing windmills of this type to increase their efficiency and to reduce their losses.